Migrate type checking from mypy to ty (#237)

* Migrate type checking from mypy to ty

* Address ty migration review feedback

Author: dhruvmanila

.github/workflows/main.yml

@@ -25,8 +25,7 @@ jobs:
         run: uv run --locked pytest
       - name: Run pre-commit checks
         run: uv run --locked pre-commit run --verbose --all-files --show-diff-on-failure
-      # FIXME: mypy is failing due to missing types-* packages
-      # - name: Run mypy
-      #   run: uv run --locked mypy algorithms_keeper/ tests/
+      - name: Run ty
+        run: uv run --locked ty check
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v3

.gitignore

@@ -6,7 +6,6 @@
 
 # Tests
 .pytest_cache/
-.mypy_cache/
 __pycache__/
 
 # Local stuff

README.md

@@ -4,7 +4,7 @@
 [![CI](https://github.com/TheAlgorithms/algorithms-keeper/actions/workflows/main.yml/badge.svg)](https://github.com/TheAlgorithms/algorithms-keeper/actions/workflows/main.yml)
 [![codecov](https://codecov.io/gh/TheAlgorithms/algorithms-keeper/branch/master/graph/badge.svg?token=QYAZ665UJL)](https://codecov.io/gh/TheAlgorithms/algorithms-keeper)
 [![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://docs.astral.sh/ruff/)
-[![Checked with mypy](https://img.shields.io/static/v1?label=mypy&message=checked&color=2a6db2&labelColor=505050)](http://mypy-lang.org/)
+[![ty](https://img.shields.io/badge/ty-2a6db2)](https://docs.astral.sh/ty/)
 
 </div>
 
@@ -52,12 +52,13 @@ Some actions of the bot can be triggered using commands:
 ## Development
 
 Install [uv](https://docs.astral.sh/uv/getting-started/installation/), then set up
-the project and run tests from the repository root:
+the project, run tests, and check types from the repository root:
 
 ```shell
 uv sync
 uv run pytest
 uv run pre-commit run --all-files
+uv run ty check
 ```
 
 Ruff handles Python linting and formatting through the pre-commit hooks.

algorithms_keeper/__main__.py

@@ -86,7 +86,11 @@ async def main(request: web.Request) -> web.Response:
             # Give GitHub some time to reach internal consistency.
             await asyncio.sleep(1)
             if logger.isEnabledFor(logging.DEBUG):
-                callbacks = [func.__name__ for func in main_router.fetch(event)]
+                # Router callbacks can be callable instances without __name__.
+                callbacks = [
+                    getattr(func, "__name__", type(func).__name__)
+                    for func in main_router.fetch(event)
+                ]
                 logger.debug("event=%s callbacks=%s", event_info, callbacks)
             await main_router.dispatch(event, gh)
         if gh.rate_limit is not None:  # pragma: no cover

algorithms_keeper/parser/rules/naming_convention.py

@@ -44,7 +44,7 @@ def valid(self, name: str) -> bool:
 
 
 class NamingConventionRule(lint_rule.ReviewLintRule):
-    METADATA_DEPENDENCIES = (QualifiedNameProvider,)  # type: ignore
+    METADATA_DEPENDENCIES = (QualifiedNameProvider,)
 
     VALID = [
         Valid("type_hint: str"),
@@ -152,7 +152,7 @@ def visit_AnnAssign(self, node: cst.AnnAssign) -> None:
     def visit_AssignTarget(self, node: cst.AssignTarget) -> None:
         self._assigntarget_counter += 1
 
-    def leave_AssignTarget(self, node: cst.AssignTarget) -> None:
+    def leave_AssignTarget(self, original_node: cst.AssignTarget) -> None:
         self._assigntarget_counter -= 1
 
     def visit_ClassDef(self, node: cst.ClassDef) -> None:

pyproject.toml

@@ -15,34 +15,24 @@ dependencies = [
 
 [dependency-groups]
 dev = [
-  "mypy",
   "pre-commit",
   "pytest==9.1.1",
   "pytest-aiohttp==1.1.1",
   "pytest-asyncio==1.4.0",
   "pytest-cov==7.1.0",
+  "ty==0.0.78",
 ]
 
 [tool.uv]
 package = false
 
-[tool.mypy]
-ignore_missing_imports = true
-warn_unused_configs = true
-warn_unused_ignores = true
-warn_redundant_casts = true
-warn_return_any = true
-check_untyped_defs = true
-disallow_untyped_defs = true
-disallow_untyped_calls = true
-disallow_untyped_decorators = true
-disallow_subclassing_any = true
-no_implicit_optional = true
+[tool.ty.src]
+include = ["algorithms_keeper", "tests"]
+# Parser fixtures intentionally omit required annotations.
+exclude = ["tests/data"]
 
-[[tool.mypy.overrides]]
-module = "tests.data.*"
-disallow_untyped_defs = false
-check_untyped_defs = false
+[tool.ty.terminal]
+error-on-warning = true
 
 [tool.ruff]
 line-length = 88

tests/test_main.py

@@ -1,3 +1,7 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
 import pytest
 import pytest_asyncio
 from aiohttp import web
@@ -6,9 +10,13 @@
 
 from .utils import number
 
+if TYPE_CHECKING:
+    from aiohttp.test_utils import TestClient
+    from pytest_aiohttp.plugin import AiohttpClient
+
 
 @pytest_asyncio.fixture()
-async def client(aiohttp_client):  # type: ignore
+async def client(aiohttp_client: AiohttpClient) -> TestClient:
     app = web.Application()
     app.router.add_get("/", main.index)
     app.router.add_get("/health", main.health)
@@ -17,7 +25,7 @@ async def client(aiohttp_client):  # type: ignore
 
 
 @pytest.mark.asyncio
-async def test_ping(client):  # type: ignore
+async def test_ping(client: TestClient) -> None:
     headers = {"X-GitHub-Event": "ping", "X-GitHub-Delivery": "1234"}
     data = {"zen": "testing is good"}
     response = await client.post("/", headers=headers, json=data)
@@ -26,15 +34,15 @@ async def test_ping(client):  # type: ignore
 
 
 @pytest.mark.asyncio
-async def test_failure(client):  # type: ignore
+async def test_failure(client: TestClient) -> None:
     # Even in the face of an exception, the server should not crash.
     # Missing key headers.
     response = await client.post("/", headers={})
     assert response.status == 500
 
 
 @pytest.mark.asyncio
-async def test_success(client):  # type: ignore
+async def test_success(client: TestClient) -> None:
     headers = {"X-GitHub-Event": "project", "X-GitHub-Delivery": "1234"}
     # Sending a payload that shouldn't trigger any networking, but no errors
     # either.
@@ -44,15 +52,15 @@ async def test_success(client):  # type: ignore
 
 
 @pytest.mark.asyncio
-async def test_index(client):  # type: ignore
+async def test_index(client: TestClient) -> None:
     response = await client.get("/")
     assert response.status == 200
     assert response.headers["content-type"] == "text/html"
     assert "algorithms-keeper" in (await response.text())
 
 
 @pytest.mark.asyncio
-async def test_health(client):  # type: ignore
+async def test_health(client: TestClient) -> None:
     response = await client.get("/health")
     assert response.status == 200
     assert await response.text() == "OK"

tests/test_rules.py

@@ -100,7 +100,7 @@ def test_rules(
             "\n".join(str(e) for e in reports),
         )
 
-        report = reports[0]  # type: ignore
+        report = reports[0]
 
         if test_case.range is not None:
             assert test_case.range == report.range